[SOLVED] First build. Need advice on fan setup

[Thundersticks]

So it's my first build and im all good to go apart from a small query regarding case fans - this subject seems to be most divisive when trying to research your first build. I've bought the NZXT H510 which comes with two 120mm exhaust fans pre installed (top and rear). I was wanting to get another 2 NZXT F120 (or 140mm if I can get them soon) fans which would both be front intakes.

Here comes my problem. I have the Gigabyte X570 Auros elite mother board and Ryzen 3700x with supplied wraith prism cooler. My mobo has 4 fan headers from what I can tell (CPU_FAN, CPU_OPT and 2X SYS_FAN) and therefore I was thinking of doing this:

CPU cooler into CPU_FAN
An exhaust fan into each SYS_FAN
Both intake fans into the CPU_OPT by using a Y splitter.

My question is would this work and enable me to still monitor and control all fans? Or are there more optimal ways of setting this up which I am missing.

Thanks

 

[tennis2]

Looks fine to me!

 

[beyondlogic]

the issue with using the water cooling fan header is you may not be able to run 2 fans off that one and i wouldnt really recomend it

140mm fans will run quieter due to not needing to spin as fast e.g some 120mm fans will run at 2000rpm while the 140mm fans can run at 1500rpm and push the same air

personally id run the 120mm rear on a molex connector since its exaust

as anything running on a cpu cooler fan header unless pwm controlled splitter wont run at the right speed

 

[Karadjgne]

Leave cpu_fan alone. Lol. For obvious reasons.

To optimize airflow, you'll want one strong source in and one strong source out. To get that you'll want fan groups in concert. I'd use 2x 2way splitters. One on the intakes, making both fans respond the same, one source, and one on the exhausts, making them respond the same. Both splitters will go to the sys_fan headers. Not the cpu_opt, which remains empty.

You don't need to monitor individual fans. Since splitters work by only using 1 speed sense wire, all fans on that header/splitter respond to the same duty cycle. If you have a 1000rpm fan at sense and a 1500rpm fan at secondary, at 50% duty cycle, the sense fan is at 500rpm± and the 1500rpm fan is at 750rpm±. Not hard math. With 2x identical fans, both spin at the same rate.

 

[Thundersticks]

Thanks very much and sorry for the slow reply. Fan configuration has been by far the hardest topic to research with everyone having different solutions based their own needs and experience.

I like the sound of using 2x splitters and having intake and exhaust fans into single headers. This way it'll be easy for me to monitor the system airflow as a whole and see if either input or exhaust begins to labour.

I did some more reading and all 4 headers are basically identical hybrid headers and just labelled for suggested use. Karadjgne's suggestion should leave the cpu_opt free for future use if needed and I'll keep an eye on fan burden and temps to see If I need to reconsider any of the setup in future.

Thanks again.

 

[Paperdoc]

Karadjgne is right. And here's one particular reason. Any mobo has at least TWO very similar fan control systems that differ in one important aspect. Each fan header concentrates on monitoring a TEMPERATURE via a sensor, and controlling the speed of its fans to keep that measured value on target. The CPU_FAN header always uses a sensor inside the CPU chip, since it is cooling that chip. A CPU_OPT header almost always uses that same temp sensor. The SYS_FAN or CHA_FAN headers use a different sensor built into the mobo normally, although some allow you to choose to use the CPU internal sensor IF you connect to that header a fan for some unusual use. So for both the front intake fans and the rear exhast fans you are ventilating the entire case, and the correct sensor to use it the motherboard one. That sensor normally is NOT available to the CPU_FAN or CPU_OPT header. Those fans should be connected to SYS_FAN or CHA_FAN headers and their configurations checked to be sure they are using the motherboard temp sensor IF there is a choice offered.